Transducer



United States Patent Ofitice 2,771,513 Patented Nov. 20, 1956 TRANSDUCER Clarence F. Jensen, Racine,

Electric Company, Racine, ware Wis., assignor to Webster Wis., a corporation of Dela- The present invention relates to an electromechanical transducer and has for one of its primary objects the provision of a new and improved transducer which is especially suitable as a pickup for use in the reproduction of sound from records.

A further object of the present invention is to provide a new and improved transducer characterized by its light weight, low inertia and suitability for use in connection with multi-stylus pickups.

Another object of the present invention is to provide a new and improved rnulti-stylus transducer utilizing a ceramic type of transducer element.

A still further object of the present invention is to provide a new and improved transducer of the multistylus type utilizing two edge mounted ceramic elements connected and actuated by a vertically disposed stylus holder andelectrically connected in series additive relation whereby a greater output is obtainable from the transducer.

In brief, the transducer of the present invention includes either one or two transducer elements of the ceramic type. These are mounted in a cartridge type of housing comprising two like but opposed parts held together by suitable means such as rivets. element or elements are mounted within a recess or chamber in the housing, and they are preferably mounted edgewise in generally diagonal crossed position, whereby elements of greater length and two elements may be utilized without materially increasing the size of the device. The transducer elements are actuated by a stylus holder having two styli associated therewith and either one of which may be selected for use.

chuck, preferably disposed generally vertically, and mounted for movement about a generally transverse axis, and preferably one that is horizontally disposed and located intermediate the ends of the holder. Projecting from the holder toward the element is an ele- Fig. 2 is a vertical cross sectional view centrally of the transducer illustrated in Fig. 1;

used, then these being Fig. 3 is a fragmentary horizontal cross sectional view taken along the line 3 3 of Fig. 2; and

Fig. 4 is a view similar to Fig. 2 of a transducer utilizing two transducer elements instead of one.

Referring now to the drawing and first to Figs. 1 and 2, it may be noted that the transducer of the present invention is illustrated as being a pickup indicated as a whole by reference character 10. It comprises a housing 12 including opposed identical sections 14 and 16 which may be secured together 18 which pass through reduced width end portions of the housing. Housing sections may be made of suitable materials, such as plastics.

The pickup illustrated is of the multi-stylus type adapted particularly for playing records of diiferent types, such as conventional and long playing records. It includes a stylus 20 for playing conventional records and a second stylus 22 for playing long playing records. The styli may be of any suitable construction, but, as illustrated, each includes an osmium tipped length of wire 24 securely fastened to a shank 26 whereby the stylus may be operatively connected to a stylus actuated element;as illustrated the stylus is secured in a stylus holder indicated as a whole by reference character 28.

The styli project beyond the opposite edges of the housing so that they may be selectively positioned to engage a record. For example, the pickup can be rotatably supported in an associated tone arm (not shown) so that one or the other of the styli extends downwardly for engagement with a record placed upon an associated turntable. The means for so rotatably securing the pickup to the tone arm forms no part is therefore not shown.

In the embodiment of the invention illustrated in Figs. 1 and 2, the transducer is shown as comprising a single transducer element 30. It is of the so-called ceramic of the present invention and type and its particular construction forms no part of the present invention. It is sufiicient to say that the element is thin and light and of generally ribbon-like configure; It is also preferably mounted in what might be cesses 36 at the front and top and bottom edges.

The transducer element 30 is supported at its rear end between a pair of generally triangular mounting blocks ment and the one not shown would be at the opposite side. These, as may be noted from the drawing, are located in the narrow width portion 32b of in a suitable manner as by rivets transversely extending shaft portion 52 defining a generally horizontal axis around which the stylus holder is moved in response to excursions of the stylus in the record groove. The holder and supporting shaft are mounted under some degree of compression between the front edge portions 33 as in a journal bearing structure 54 of suitable damping material substantially surrounding the front portion 52F. The rear portion 52R of the shaft, however, is journalled for rotation in a bearing block 56 which may be of Bakelite or other plastic, such for example, as that of which the housing is made.

The stylus holder is operatively connected to the trans ducer element in such a manner that oscillatory movement of the holder about the axis of the horizontal shaft 52 bends the transducer element. This operative connection is made through a rearwardly extending arm 60 preferably formed integral with the holder 50 and having spaced apart bifurcations 62 at its outer end adapted to be secured to the outer or free end of the transducer element through a pad 64 of damping material. It may be noted that the holder is of such construction that it can be fabricated as by a stamping operation, whereby the bifurcations 62 are readily made.

From the foregoing detailed description of the present invention it is apparent that the transducer can be constructed readily and economically and that it is small, light and rugged in construction. A transducer element of substantial length can be utilized even though the transducer itself is quite small. For example, the transducer illustrated is four times actual size. The device has been found to have good operating characteristics and to produce a good voltage output. It has been found that, in order to get greater output from the relatively smaller excursions of the stylus when playing the socalled long playing records, the stylus 22, which is nearest to the movable end of the transducer element, is the one used in playing the long playing records.

The principles of the present invention lend themselves particularly well to the construction of a transducer having a plurality of transducer elements. An arrangement of this character is illustrated in Fig. 4, from which it can be seen that two elements 3t) and '70 are utilized. They are both mounted edgewise in spaced apart diagonal cross relationship, whereby both can be mounted in a housing of practically the same size as used for a single transducer element. The construction is very much like that of Figs. 1 and 2 except for the provision of a second arm 73 (corresponding to arm 60) and mounting blocks 74 (corresponding to blocks 38) for element 70 and the conductors 76, 78, and 80 for connecting the elements 30 and 70 in series additive relation. It has been found that a transducer constructed and arranged in accordance with Fig. 4 has a voltage output about fifty percent greater than one using a single transducer element.

While the present invention has been described in connection with the details of illustrative embodiments, it should be understood that these details are not intended to be limitative of the invention except in so far as set forth in the accompanying claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A transducer, including in combination, a stylus actuated element having a generally vertically extending portion adapted to be actuated by a stylus, means supporting said element for movement in a plane substantially perpendicular to a horizontal axis, and a pair of bender type transducer elements connected to said vertically extending portion at points spaced on opposite sides of said horizontal axis.

2. A transducer, including in combination, a housing, a stylus holder in said housing having a generally vertically extending portion and adapted to receive a stylus at each end, means supporting said stylus holder between its ends for movement about a generally horizontal axis, and bender type transducer elements connected to said holder, one near each end of the latter, said elements being disposed in spaced apart cross diagonal relation in said housing.

3. A transducer, including in combination, a stylus actuated element having a generally vertically extending portion adapted to be actuated by a stylus, a generally horizontally disposed shaft secured to said element and including portions extending forwardly and rearwardly therefrom, a housing for said element, means including a journal bearing for the forwardly extending portion of said shaft and an apertured bearing block receiving the rearwardly extending portion for supporting said element for movement about a horizontal axis in said housing, and a bender type transducer element connected to said actuated element at a point spaced from said shaft.

4. A transducer, including in combination, a generally vertically disposed stylus actuated element, a generally horizontally disposed shaft secured to said element and including portions extending forwardly and rearwardly therefrom, a two-part housing including opposed edge portions adapted to be brought together for defining a recess for said element, means for supporting said element on said housing comprising a journal bearing of damping material for the forwardly extending portion of said shaft and an apertured bearing block receiving the rearwardly extending portion, said journal bearing being clamped between adjacent edge portions of the housing part and said block being clamped by the housing parts in said recess, and a bender type transducer element mounted in said housing and having one end connected to said actuated element at a point spaced from said shaft, and means including mounting blocks of damping material clamped in said recess by the housing parts for supporting the opposite end of said transducer element.

5. A transducer, including in combination, a generally vertically disposed stylus actuated element, a generally horizontally disposed shaft secured substantially centrally to said element and including portions extending forwardly and rearwardly therefrom, a two-part housing including opposed edge portions adapted to be brought together for defining a recess for said element, means for supporting said element on said housing comprising a journal bearing for the forwardly extending portion of said shaft and an apertured bearing block receiving the rearwardly extending portion, said journal bearing being clamped between adjacent edge portions of the housing part and said block being clamped by the housing parts in said recess, and bender type transducer elements mounted in said housing, each of said elements having one end connected to said actuated element at a point spaced from said shaft, and means including mounting blocks of damping material clamped in corners of said recess by the housing parts for supporting the opposite ends of said transducer elements.

6. A transducer including a pair of spaced apart and crossed transducer elements, means supporting two adjacent ends of said elements, and stylus actuated means for deflecting the other ends of said elements.

I 7. A transducer, including a pair of spaced apart and crossed edge mounted transducer elements, means supporting two adjacent ends of said elements, and vertically disposed stylus holder means connected to the other ends of the elements for deflecting them.

8. A transducer, including in combination, a stylus actuated element having a generally vertically extending portion, means supporting said element for movement about a generally horizontal axis some distance from both ends of said element, and a pair of bender type transducer elements having end portions connected to said actuated element at points on opposite sides of said axis, said points being disposed within a single plane including said axis and said vertically extending portion.

9. A transducer, including in combination, a housing, a stylus actuated element in said housing having a generally vertically extending portion, a stylus secured to References Cited in the file of this patent UNITED STATES PATENTS Courcy et al. Jan. 23, 1945 Jafiee Oct. 18, 1949 Luke Mar. 20, 1951 Bauer Aug. 28, 1951 Cordes Nov. 20, 1951 Munroe Jan. 1, 1952 

